When they aren’t talking about toxins, anti-vaccine folks like to talk about two things – the gut and the blood-brain barrier (BBB).

Kelly Brogan, a holistic psychiatrist, missed an opportunity to talk about the gut when scaring folks about “toxins” in flu shots and the blood-brain barrier.

Sometimes they talk about all of them together.

What is the Blood-Brain Barrier?

The blood-brain barrier is exactly what you think it is – a barrier to keep substances in the blood from entering the cerebrospinal fluid that surrounds the brain and spinal cord.

Of course, the blood-brain barrier is not impermeable, as some substances, like glucose, ketone bodies, and amino acids have to get to the brain. Brain cells need fuel, just like every other part of the body. And waste products have to get from the brain, across the blood-brain barrier, and back into the blood, so that we can get rid of them.

So the blood-brain barrier doesn’t block everything though. Instead, it is a semi-permeable membrane that lets some things through, but keeps out foreign substances (neurotoxins), lipid insoluble molecules, large molecules (macromolecules), and molecules with a charge.

Why is all of this important?

With a functioning blood-brain barrier, many medications, hormones, and toxins, are kept from affecting our brains! Of course, the blood-brain barrier can make it hard when you do want something to affect your brain, like when you are treating meningitis, anxiety, depression, or migraines.

And there are times when the blood-brain barrier can break down, like after a stroke, certain infections, head trauma, or having high blood pressure, etc.

When Does the Blood-Brain Barrier Form?

It shouldn’t be surprising that none of the things that anti-vaccine folks say about the blood-brain barrier is true.

“In contrast with the rodent, in which the development of the BBB occurs primarily after birth, the human barrier and its tight junction protein complex develop mainly in utero. More recent evidence has confirmed that the proteins of the tight junction complex are present very early during human fetal brain development.”

Fetal and Neonatal Physiology (Fifth Edition)

So, of course, the blood-brain barrier forms before a baby is born.

“Given sufficient time and dosage most drugs can breach the placenta and enter the fetal circulation, posing a teratogenic risk to the fetal brain. Although the placenta and BBB have several efflux transporters in common, the BBB is a far more structurally complex and restrictive system.”

The placenta does a good job of most things from getting to your baby, but once inside, you don’t want everything in your baby’s blood to get to their brain, right?

That’s why the blood-brain barrier begins to form well before your baby is born.

“The BBB develops during fetal life and is well formed by birth, especially to proteins and macromolecules.”

Abbott et al on the Structure and function of the blood-brain barrier

And it is well formed by the time they are born.

None of the ingredients in vaccines, whether it is aluminum, polysorbate 80, or anything else, is going to cross the blood-brain barrier and act as a toxin.

“One can question why polysorbate-80 is in the vaccines if it serves to potentially transport vaccine materials across the blood-brain-barrier. After all, what vaccine materials need to enter the brain? The obvious answer is, none. I’ve heard people ask if the polysorbate-80 is in the vaccines intentionally, used as part of a medical experiment on the human race, like we heard about during World War II.”

It should be clear that these ideas about the blood-brain barrier are just more myths to scare you away from vaccinating and protecting your kids.

Polysorbate 80, for example, is an emulsifier that helps ingredients mix together. It is also used in ice cream and other foods. Maybe someone can ask Dr. Palevsky if he thinks that’s why we sometimes get a ‘brain freeze’ when we eat ice cream – the polysorbate 80 is allowing the ice cream to cross our blood-brain barrier and literally freeze our brain as some kind of medical experiment on the human race.

What to Know About Vaccines and the Blood Brain Barrier

The blood-brain barrier is a semi-permeable membrane that develops before your baby is born. Review how that should affect your decision to vaccinate your kids.